Thank you for the model number. Grundfos e-mailed me and proposed the UP20-15N. stainless body, etc.; max head: 4ft; 2.6 GPM @ 3ft; 5.2 GPM @ 2ft; 7.4GPM @ 1ft.
My main concern though is that the performances are much lower than your pump or the likes of the little giant. Do you think this pump is too weak?
I sent another request with your model number as a reference, they must have a European (220V) equivalent. But I don

That is a bit too low of a flow. Here's why: Using a 15 gallon keg setup as an example, they are about 3.5' tall. So, a valve at the base would drop down to a valve ahead of the pump, + a 90 deg. elbow (adds resistance), then a short nipple, another 90 deg. elbow (more resistance), then a rise up to the pump inlet of about 8", then about 4.5' feet to the top of the keg and then 2 more 90's and a valve (more resistance). This estimated head totals around 5.5'. That pump won't lift the load in this example as it's maximum head is 4'! The other one, however, is rated 5.1 GPM @ 5', so you'd probably get 4.5 GPM @ that head. They do make another step up, but it is around $200 USD and would be a bit of overkill for this use.

Another consideration is that you can build a system that will recirculate runoff, pump sparge water and pump runoff to the kettle using only 1 pump. The change over is acomplished by opening and closing valves. The other pump would stop pumping wort into the kettle when it was less than half full due to the back pressure of the liquid. The pump I recommend will fill it at full throttle.